1. Field of the Invention
This invention relates to system and method of controlling voltages in a printing apparatus, and more particularly to a system and method of controlling voltages in a printing apparatus employing a charged substrate and toner.
2. Description of the Related Art
In a certain printing method, the image to be reproduced is partitioned into mutually exclusive areas called "halftone cells," each containing a number of pixels. When halftone cells are used with a developable image printer, gray levels are simulated by exposing a subset of the total number of pixels in a halftone cell, to attract toner to the exposed pixels. The pixels are too small for a viewer to perceive individual pixels, and the viewer instead perceives a gray level corresponding to the percentage of halftone cell area that is covered with toner.
Numerous physical conditions within the developable image printer affect various aspects of the appearance of a halftone cell. A variation in a single physical condition may cause a variation in multiple aspects a cell's appearance.